1. Field of the Invention
The present invention relates to an electromagnetically actuatable pressure modulator for anti-locking brake systems of automotive vehicles.
2. Description of Related Art
Commonly assigned U.S. patent application Ser. No. 899,201, filed Aug. 21, 1986, allowed discloses a pressure modulator which detects a threat of overbraking of an automotive vehicle wheel, and reduces the brake pressure in the wheel brake cylinder to allow the braked wheel to accelerate again. The disclosures of Ser. No. 899,201 are incorporated herein by reference.
Related developments are disclosed in commonly assigned U.S. Pat. No. 4,511,971; U.S. patent applications Ser. No. 899,212, now U.S. Pat. No. 4,691,813 issued Sept. 8, 1987, and Ser. No. 899,208, now U.S. Pat. No. 4,717,211 issued Jan. 5, 1988, both filed Aug. 21, 1986; and U.S. patent application Ser. No. 22,738, filed Mar. 6, 1987, of even date herewith. These disclosures are also incorporated herein by reference.
The pressure modulator according to Ser. No. 899,201 has a transmission for transmitting forces with a variable step-up ratio between the pressure relief piston, on the one hand, and, on the other hand, the magnet armature and/or compression spring which bias the pressure relief piston. The transmission is so developed that a linear force on the pressure relief piston results from the difference between the non-linear armature force and the non-linear spring force.